Avoiding Influenza, Flu-Like Illness Might Protect Against Stroke

​​By staff

New York—Here’s another reason why pharmacists should heavily promote vaccination against influenza: It could help protect patients against stroke.

New research suggests that flu-like illnesses are linked to an increased risk of stroke and neck artery dissection. The studies were presented recently at the American Stroke Association’s International Stroke Conference 2019 in Honolulu.

In the first study,Columbia University–led researchers determined that having influenza-like illness (ILI) increased the odds of having a stroke by nearly 40% over the next 15 days and that the heightened risk persisted for a year.

Included in the study were 30,912 patients identified as having an ischemic stroke in 2014. ILI in the 15 days before a stroke was associated with an overall increase in odds of stroke (OR = 1.39, 95% CI, 1.09-1.77).

“We were expecting to see differences in the flu-stroke association between rural and urban areas. Instead we found the association between flu-like illness and stroke was similar between people living in rural and urban areas, as well as for men and women, and among racial groups,” explained lead author Amelia K. Boehme, PhD.

In the second study, researchers from the same university reviewed 3,861 cases of first nontraumatic cervical artery dissection within the New York State Department of Health Statewide Planning and Research Cooperative System (2006-2014). They found 1,736 instances of flu-like illness and 113 of influenza during the 3 years preceding cervical artery dissection (CeAD), which is a leading cause of ischemic stroke in younger patients aged 15 to 45 years.

Results indicated that patients were more likely to have ILI within 30 days of CeAD compared with the same time 1 and 2 years before (0-15 days: adjusted OR 1.53, 95% CI, 1.02 - 2.30; 0-30 days: adjusted OR 1.60, 95% CI, 1.14 - 2.23).

“Our results suggest that the risk of dissection fades over time after the flu. This trend indicates that flu-like illnesses may indeed trigger dissection,” lead author Madeleine Hunter, a second-year medical student, points out.

“ILI may increase risk of CeAD for up to one month,” study authors conclude, adding, “Further research on mechanisms by which ILI and influenza may trigger dissection is warranted.”